On Tue, 2008-11-18 at 12:10 -0800, msoulier wrote: > Hello, > > I have a daemon process running using the Django ORM API to access/ > modify tables in PostgreSQL. I just ran into an issue where it looks > like the process is keeping read-locks on the tables that it is > reading, which is preventing a subsequent write lock from granting. > > Does the ORM API normally lock tables? If so, when are the locks > released?
Django doesn't do any explicit table locking, although there are transactions involved. However, that shouldn't be affecting this. SELECT statements require an "ACCESS SHARE" lock on a table and INSERT or UPDATES take a "ROW EXCLUSIIVE" lock, which doesn't conflict with "ACCESS SHARE". So selects from the same table in a different transaction are possible to be concurrent with writes (the selects just won't see the newly written data until that transaction is committed). So there shouldn't be any lock waiting going on there. You just say "read locks", but that isn't a defined postgreSQL lock name, so can you be more specific? Look in the pg_locks system view when this problem is going on and track down who is waiting on what locks and it might help diagnose the problem a bit more. Regards, Malcolm --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
